1. Field of the Invention
The present invention relates to novel compositions useful for the production of ceramic materials, to various processes for the preparation thereof, and to the manufacture of sintered ceramic shaped articles therefrom.
2. Description of the Prior Art
It is known to this art that the use of yttrium oxide by itself as a ceramic powder is unsatisfactory because granular growth occurs too rapidly during the densification thereof. The material must be sintered at a very high temperature, generally above 1,700.degree. C. Without the aid of an external pressure, supplied, for example, by sintering under load or by an isostatic compacting with heating, the density remains limited by the intragranular porosity at about 95% of the theoretical density. This residual porosity and the grain size are detrimental to the desired properties of the final product, especially the mechanical properties thereof.
Thus, need exists in this art for means to accelerate the densification process relative to that of the granular growth. It would then be possible to provide ceramics which have high densities at a lower temperature, final densities closer to the theoretical density and an improved microstructure.